No, I don't think the whole concept of an RPG is a skinner box. A skinner box is created for study of animals.

The RPG - originally - was about playing a role in a fantasy environment, where you could explore the world and yourself. Beyond that, it has elements of several genres. A good RPG tells a good story - with an outcome you can change according to your actions. It has both strategic and tactical gameplay - in the form of character development and combat. They also tend to include secrets and puzzles to challenge the mind in other ways.

Calling them skinner boxes is to misunderstand the genre and focus exclusively on those elements.

That said, we can agree that too many modern RPGs (MMORPGs specifically) tend to focus on "skinner box elements" more than the story or the roleplaying aspects. I think that's really sad - but it has nothing to do with the genre in itself.

As for modern developers in charge of big projects - they're not so much developers as they're publisher extensions. They're just working in a professional capacity to accomplish the goals set by the people who carry the investment.

The skinner box design blueprint is not created to get us addicted, it's nothing quite so malicious. It's there because it works and - primarily - because it's a very cheap way of extending the lifetime of a game. You don't have to invest much beyond the initial platform, which is why the model is so popular and widespread. I don't think publishers are cruel or that they really want to hypnotize us. They're just doing the human thing - which is to take the path of least resistance. They're businessmen, so they minimise effort and maxmise profit - and that's where the skinner box excels.